NCT06961344

An Open-label Extension Safety Study of MELAS Patients Who Completed TIS6463-203 (PRIZM)

An Open-label Extension Study Evaluating the Safety of Zagociguat in Participants With MELAS Who Completed TIS6463-203

• Status: Enrolling By Invitation
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 44 (estimated)
• Sponsor: Tisento Therapeutics · Industry
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

Summary

The goal of this clinical trial is to evaluate the long-term safety and tolerability of zagociguat in patients with MELAS who completed study medication treatment in the lead-in study TIS6463-203. TIS6463-204 is evaluating zagociguat in an open-label extension study at the daily dose of 15mg. The study medication is a once daily oral table and will be provided at the clinic and/or shipped to the participant's home. Study assessments will be conducted during clinic visits which will occur at three months and then at six months. Thereafter, clinic visits will occur every six months.

Detailed description

On Screening Visit Day -1 (which corresponds to Period 2 Week 12 Visit from lead-in study TIS6463-203), participants will sign the informed consent form, be confirmed eligible for this open-label extension study and undergo Screening Visit assessments. Eligible participants will begin dosing the next day on Day 1 (there is no Day 0) at home. Participants will have a 3-month visit and 6-month study visit at the clinic and thereafter will have a clinic visit every 6 months. Participants should have a Follow-up Visit 4 (+1) weeks after zagociguat discontinuation.

Conditions

• Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-Like Episodes (MELAS Syndrome)

Interventions

Type	Name	Description
DRUG	zagociguat 15mg	once daily oral tablets

Timeline

• Start date: 2025-08-18
• Primary completion: 2028-07-01
• Completion: 2028-07-01
• First posted: 2025-05-07
• Last updated: 2026-03-12

Locations

15 sites across 5 countries: United States, Australia, Germany, Italy, United Kingdom

Regulatory

• FDA-regulated drug study